White Smoke

[Gelbster]

Don't speculate - diagnosis it?
Just measure the vacuum at the AOS - lots in Search/DIY.You need a manometer to do this.Your Indie should have one. Replacing the AOS on a whim may not yield any improvement in the smoke for a few seconds after start-up.
As others have hinted ,the cause may be benign but they did not explain. Others will do a better job than me -but here is a beginning at an explanation - the flat engine configuration may be the problem. Oil tends to slowly drain & pool to places where it combines with the combustion mixture in the first few revolutions of the engine after starting.In a vertical engine, oil in the upper part of the cylinder bores would drain past the rings, down into the sump. In the flat engine it accumulates in the lower portion of the bores but 'above' the piston rings.There is no gravity drainage part the rings.
The next stage is to find out which cylinder is worst and why.That is another thread.

[2000986s]

Originally Posted by Gelbster

Don't speculate - diagnosis it?
Just measure the vacuum at the AOS - lots in Search/DIY.You need a manometer to do this.Your Indie should have one. Replacing the AOS on a whim may not yield any improvement in the smoke for a few seconds after start-up.
As others have hinted ,the cause may be benign but they did not explain. Others will do a better job than me -but here is a beginning at an explanation - the flat engine configuration may be the problem. Oil tends to slowly drain & pool to places where it combines with the combustion mixture in the first few revolutions of the engine after starting.In a vertical engine, oil in the upper part of the cylinder bores would drain past the rings, down into the sump. In the flat engine it accumulates in the lower portion of the bores but 'above' the piston rings.There is no gravity drainage part the rings.
The next stage is to find out which cylinder is worst and why.That is another thread.

Wow this is incredibly educational, thanks for the post!

[Gelbster]

Originally Posted by 2000986s

Wow this is incredibly educational, thanks for the post!

You are welcome, that is why your 986 Membership is worth every penny !
Credit should go to people like Ben who write:
DIY cheap vaccum gauge inWC
Note ,even a new AOS can be defective
http://986forum.com/forums/general-discussions/60203-new-aos-failing.html
video:
https://www.youtube.com/watch?v=ipkQUKkUcJk

[2000986s]

yessir!

[rexcramer]

Originally Posted by Gelbster

As others have hinted ,the cause may be benign but they did not explain. Others will do a better job than me -but here is a beginning at an explanation - the flat engine configuration may be the problem. Oil tends to slowly drain & pool to places where it combines with the combustion mixture in the first few revolutions of the engine after starting.In a vertical engine, oil in the upper part of the cylinder bores would drain past the rings, down into the sump. In the flat engine it accumulates in the lower portion of the bores but 'above' the piston rings.There is no gravity drainage part the rings.
The next stage is to find out which cylinder is worst and why.That is another thread.

VW's and Subaru flat engines, with lots of miles, can smoke on start up after sitting for awhile also. Trying to pull the oil cap off while the engine is running is a 'shade tree' mechanic test. A manometer would definitely dial it in for you. How many miles on your engine? Once after a week, most likely a non-issue, depending on mileage. Definitely don't ignore it, if it continues. A compression test and or a leak-down test might also shed some light too.